There is no evidence that Peter was ever in modern day Iraq. And there is good reason to believe that if Peter had been in Iraq, the believers there would have been quite vocal about that, as a matter of honor and prestige.
-A8
"There is no evidence that Peter was ever in modern day Iraq" He was in Babylon according to 1 Peter 5:13 where he wrote this first epistle circa 65 AD. It was not even part of the Roman Empire then, but part of the Parthian Empire with a substantial Jewish population centering around the Babylonian Talmud.